Improvement in metal frames for pianos



FFTGE.

MARTIN MARTINS, OF NEY YORK, N. Y.

IMPROVEMEN'l IN METAL FRAMES FOR PIANOS.

Specification forming part of Letters Patent No. 57,743, dated September4, 1865.

To all whom t may concern.-

Be it known that I, MARTIN MARTINS, of the city, county, and State ofNew Yor'k, have invented a new and useful'Improvement in Metal Framesfor Piano-Fortes; and I do hereby declare that the following' is afull,clear, and exact description thereof, which willenable others skilled inthe art to make and use the same, reference being' had to theaccompanying drawings, forming part of this specification, in whioh-Figure l represents an inverted plan of this invention. Fig. 2 is alongitudinal section of the same.

Similar letters of reference indicate like parts.

This invention relates to certain improvements in the metal case ofpiano-fortes, said case being cast solid, with a series of longitudinaland of cross-braces, in combination with tension-screws extending underthe metal frame in a direction parallel with the strings, or nearly so,and rendered yielding and adjustable by suitable springs in such amanner that, by said tension-screws and adjustingsprings, the strain ofthe strings is counteracted, and the metal frame is held i'iat andprevented from bulging ont when exposed to a variable temperature, or bythe continuous strain of the strings. the tension-screws is regulated bythe springs, which can be compressed more or less, simply by screwingthe nuts in or out.

A represents a metal frame, cast of iron or any other suitable material,and provided on its upper or front surface with a series oflongitudinal, or transverse braces or rafters, a, which extend acrossthe frame from one rim of the same to the other, and which serve tostrengthen the frame and to render it capable of sustaining the strainof the strings. One end of the frame is provided with a doubleshoulderedbracket, b, which is intended to support the wrest-plank c. Saidwrest-plank is secured to the`-bracket b by screws or any other suitablemeans, and it is provided with a series of sockets to receive thetuning-pins g. From the tuning-pins the strings extend The strainexerted by over suitable bridges to the hitch-pins d in the usualmanner, and the bridges rise from the soundingboard, and they aresupported by suitable studs, whereby the same are elevated far enough tolet the braces or rafters a pass through under them. The hitch-pins aresecured in a metal plate, df, which is fastened to the frame A. From thelower or rear surface of the frame A project two lips, cf, and betweenthese ribs the sounding-board s is introduced, as clearly shown in thedrawings. This sounding-board is supported by pins or anyother suitablemeans, and the metalfranie Ais strengthened by a series of screw-rods,h, which extend on its rear side or lower surface parallel with thestrings, or nearly so, as shown in Fi g. l of the drawings. These screwshave their bearings at 011e end in the lip fof the frame A, and at theopposite end is an L- shaped plank, i, which is secured to the rear orlower surface of the bracket l), which supports the wrest-plank.

Suitable slots in the L-shaped plank z' serve to admit the screws, theends of which extend through springs j, which bear at one end eachagainst a stud, 7c, and at the other against the L-shaped plank t', asclearly sho wn in the drawings. By tightening the nuts l, which aref1tted on the screws on the end of rods h, the springs are strained, anda yielding strain is exerted on the metal frame A, which strain can beincreased or diminished at will. By this strain the tendency of themetal frame to bulge out or to curve by the strain of the strings iscounteracted, and a piano-forte with ametal frame is obtained, whichwill keep its tune for a long time 5 whereas piano-fortes with metalframes constructed in the ordinary manner are liable to get out of tuneby the variations of the temperature, whereby the metal frame is causedto expand and to curve or bulge out under the increased strain of thestrings.

l do not wish to confine myself, in carrying out my invention, to thepreciseform of springs shown in the drawings, since springs of anydesired form or shape may be applied, and if one spring is not sucientunder each nut, two

or more springs muy be combined until thel desired effect is produced.

Having thus described myinventiomwliatl claim as new, and desire tosecure by Letters Patent, is-

1. The tension screw-rods h and springs j, in combination with the frameA, constructed sind operating substantially its and for the purposedescribed.

2. The L-shaped plank i, in combination with the lips ef of the frame A,and with the tension screwrods h, constructed and operetingsubstantially as and for the purpose described.

MARTIN MARTINS.

Witnesses:

W M. DEAN OVERELL, M. M. LIVINGSTON.

